A thorough investigation of a regio- and stereospecific aziridine ring opening reaction presents new synthetic technology for the construction of a variety of quaternary beta-substituted-alpha-amino functional groups. Mild, metal-free reaction conditions allow for application in highly functionalized systems. This reaction has been applied to the challenging stereoselective formation of tertiary alkyl-aryl ethers. The strategy for the formation of these hindered ethers has been investigated using a variety of functionalized aziridines and phenols to determine the scope of the reaction. Other nucleophiles, such as thiolate, azide, and chloride, have also been examined to encompass the synthesis of a broader range of functionalities. This aziridine ring opening reaction manifold has demonstrated utility in assembling: beta-substituted-alpha-amino carboxamides, beta-substituted-alpha-amino esters, beta-substituted-alpha-amino silyl ethers, beta-thio-alpha-amino carboxamides, beta-azido-alpha-amino carboxamides, and beta-halo-alpha-amino carboxamides. Studies to probe the effect of the aziridine substitution patterns show that alkyl aziridines display similar reactivity to alkynyl aziridines, giving insight into mechanistic possibilities.
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http://dx.doi.org/10.1021/ja0758077 | DOI Listing |
Bioorg Chem
January 2025
N.N. Vorozhtsov Novosibirsk Institute of Organic Chemistry, Siberian Branch of the Russian Academy of Sciences, Lavrentyev Avenue 9, Novosibirsk 630090, Russia. Electronic address:
Eudesmane-type sesquiterpene lactone isoalantolactone 1 is of great interest due to its availability, biological activity and synthetic application. Respective series of original spirocyclic (11S,5') (1,2,3-triazoline-eudesma-4,15-enolides) and (11S)-aziridine-eudesma-4,15-enolides were efficiently synthesized via a chemoselective 1,3-dipolar cycloaddition reaction of organic azides to the exocyclic double bond of the lactone ring of isoalantolactone or 13E-(aryl)isoalantolactones by heating in DMF or toluene. The thermal reactions of isoalantolactone with benzyl azide, 2-azidoethanol, or n-butyl azide in 2-methoxyethanol afforded 13-(alkyamino)isoalantolactones formed as a mixture of (Z) and (E)-isomers.
View Article and Find Full Text PDFOrg Biomol Chem
January 2025
Department of Chemistry, Indian Institute of Technology Ropar, Rupnagar, Punjab, 140001, India.
Aziridines, characterized by their highly constrained three-membered nitrogen-containing heterocyclic ring system, serve as compelling synthetic intermediates for synthesizing numerous naturally occurring alkaloids and pharmaceuticals. The distinct ring strain arising from the geometric constraints of these sp-rich trigonal rings imparts high reactivity, thereby offering a wealth of intriguing synthetic opportunities. Recent advances in the chemistry and reactivity of aziridines have unveiled significant progress in preparing more complex heterocycles.
View Article and Find Full Text PDFJ Org Chem
December 2024
Department of Chemistry, University of Calcutta, 92, A. P. C. Road, Kolkata 700 009, West Bengal, India.
A series of sulfonamido-substituted oxime-ethers have been synthesized by the reaction of donor-acceptor aziridines with aldo- and keto-oximes through C-C bond cleavage. Nucleophilic attack by an oxime hydroxyl group on the -generated azomethine ylide rather than the routine cycloaddition reaction draws the novelty of the developed methodology. Selective protection of the oxime hydroxyl group is observed in the presence of phenolic -OH, which made the protocol enriched.
View Article and Find Full Text PDFChemistry
December 2024
Albert-Ludwigs-Universität Freiburg, Institute of Organic Chemistry, Albertstraße 21, 79104, Freiburg, Germany.
A (3+3)-cycloaddition to afford 2-azabiyclo[3.1.1]heptanes was realized by reacting highly strained aryl bicyclo[1.
View Article and Find Full Text PDFAngew Chem Int Ed Engl
November 2024
Polymer Synthesis Laboratory, Chemistry Program, KAUST Catalysis Center, Physical Sciences and Engineering Division, King Abdullah University of Science and Technology (KAUST), 23955, Thuwal, Saudi Arabia.
This study introduces a novel approach to inverse vulcanization by utilizing a commercially available triaziridine crosslinker as an alternative to conventional olefin-based crosslinkers. The model reactions reveal a self-catalyzed ring-opening of "unactivated" aziridine with elemental sulfur, forming oligosulfide-functionalized diamines. The triaziridine-derived polysulfides exhibit impressive mechanical properties, achieving a maximum stress of ~8.
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